Evolution by natural selection
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Evolution by Natural Selection. No Genetic Change Through Time (no evolution). Scientists believed that all organisms were exactly how they have always been. Then Lamarck came to town. Jean Baptiste Lamarck French biologist Explained evolution! Wrong  Acquired Traits.

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Evolution by Natural Selection

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Evolution by natural selection

Evolution byNatural Selection


No genetic change through time no evolution

No Genetic Change Through Time (no evolution)

Scientists believed that all organisms were exactly how they have always been.


Then lamarck came to town

Then Lamarck came to town

  • Jean Baptiste Lamarck

    • French biologist

    • Explained evolution!

    • Wrong 

    • Acquired Traits.

    • Artistic ability, Math ability, etc.


Darwin s life

Darwin’s Life

  • Charles Darwin

  • Wanted to be a doctor

    • Couldn’t stand the sight of blood

  • Married his cousin

  • Sea voyages

    • Voyage of Beagle

    • Naturalist


On the hms beagle

On the HMS Beagle

  • 5 year journey

  • Observed flora/fauna everywhere he went

    • Catalogued

    • Compared

  • Developed his theory based on observations and evidence.

  • Wrote several books

    • Most famous was “On the Origin of Species”


P s mr chaney s favorite book by darwin is

P.S. Mr. Chaney’s Favorite Book by Darwin is . . .

  • Drum roll please . . .

  • “The Formation of Vegetable Mould Through the Action of Worms.”


Darwin s theory

Darwin’s Theory

  • “Descent with Modification.”

    • All species arise from pre-existing species

    • Generations pass, and species may change if the population has:

      • Genetic Variation

      • An Overproduction of offspring

      • A Struggle to Survive

      • Differential Reproduction

        • *********Darwinian Fitness *********

So no one else figured this out until Darwin?!?!


Who has greater darwinian fitness

Who has greater “Darwinian Fitness?”


Evidence for evolution fossils

Evidence for Evolution: Fossils

  • Fossil Record

    • Rocks form in layers

    • Organisms in deeper, “older” rock, are older

    • Different organisms lived at different times

    • Today’s organisms are different from those of the past


Pennyslvania s state fossil

Pennyslvania’s State Fossil!

  • The Trilobite


Example of fossil that supports evolution

Example of Fossil that supports evolution

Megatherium


Big birds

Big Birds


Transition

Transition

  • Fossils in adjacent layers are more alike than fossils from far apart layers


Evidence of evolution transitional species

Evidence of Evolution: Transitional Species

  • Fossils of “in-between” organisms

    • Used as a timeline!

  • Speaking of trilobites . . . . Here’s a Pakicetus! (not a good transition!)

Pakicetus


Vestigial traits

Vestigial Traits

Vestige- a mark, trace, or sign


Archaeopteryx

Archaeopteryx

Bird? Or Reptile?


Vestigial traits1

Vestigial Traits

Snake “spurs”

Vestigial Wings in Drosophila

Diptera-Vestigial Wings


Xanthopan morganii praedicta

Xanthopanmorganiipraedicta

  • “Predicted Moth”

  • Darwin predicted it’s existence before it had been observed.

  • Ridiculed by other scientists

  • Orchids have specific pollinators


Let s process

Let’s Process!

  • 1. How does the presence of vestigial traits support the theory of evolution by natural selection?

  • 2. Why is variation necessary for natural selection to occur

  • 3. If a natural disaster wiped out all the small seeds in an area with a population of birds with varying beak size, how might the population be affected?


Darwinian fitness

Darwinian Fitness

Who has GREATER fitness from the perspective of Darwin, and the theory of natural selection?


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